77. That's what history has shown us

The Democrats lost the House and Senate following the 1994 AWB (which was far less objectionable than a call to ban all ammo, BTW), and Al Gore lost his home state in the 2000 elections due to his signing of the AWB.

Like I said, any attempt to ban ammo would relegate the Democratic Party to the trashcan for years to come. There's a reason President Obama hasn't said anything about gun control during his entire presidency.